FAUSSONE, Elio (Corso Appio Claudio 229/5, Torino, I-10146, IT)
CLAIMS
1. Removable pyrolysation system (1), in particular for the "in situ" heat treatment of solid urban wastes in disposal tanks (9) with energy recovery, characterised in that it comprises at least one heating bell (3) capable of being transferred adapted to define at least one pyrolysation chamber (5) to subject to a pyrolysis reaction individual areas (7) of said wastes, said heating bell (3) capable of being transferred being preferably composed of at least one layer of a material resisting to high temperatures and equipped with high-temperature heating means of said pyrolysation chamber (5) .
2. System (1) according to claim 1, characterised in that said heating means comprise at least one electric resistance (11) placed inside at least one hollow space (13) defined by an internal wall (15a) and an external wall (15b) of said bell (3) .
3. System (1) according to claim 2, characterised in that said internal wall (15a) is made of a thermally conductive material and said external wall (15b) is made of a refractory material .
4. System (1) according to claim 2, characterised in that said heating means comprise a plurality of said electric resistances (11) arranged in series or in batteries.
5. System (1) according to claim 2 or 4, characterised in that said electric resistances (11) are placed in contact with said internal wall (15a) of said bell (3) .
6. ■ System (1) according to claim 2, characterised in that between said internal wall (15a) and said external wall (15b) of said bell (3) at least one insulating layer (17) is inserted.
7. System (1) according to claim 1, characterised in that said heating means comprise at least one plasma-type torch.
8. System (1) according to claim 1, characterised in that said bell (3) is equipped with at least one automatic mixer (18) adapted to re-circulate reaction gases inside said pyrolysation chamber (5) and to move said compacted wastes in said area (7) to be treated.
9. System (1) according to claim 1, characterised in that said bell (3) is equipped with at least one withdrawal duct (27) of pyrolysis gases produced inside said pyrolysation chamber (5) .
10. System (1) according to claim 9, characterised in that it comprises at least one energy user supplied by said pyrolysis gases through said withdrawal duct (27) .
11. System (1) according to claim 9, characterised in that said withdrawal duct (27) is equipped with at least one filter with reagents.
12. System (1) according to claim 1, characterised in that said bell (3) is equipped with at least one entry duct (29) of one or more neutralising reagents inside said pyrolysation chamber (5) .
13. System (1) according to claim 1, characterised in that said bell (3) is equipped with fastening and moving means as at least one hook (20) placed on its top.
14. System (1) according to claim 1, characterised in that it comprises at least one layer of insulating material placed between an external surface of said bell (3) and surrounding walls of grooves (19) defining said area (7) to be treated.
15. System (1) according to claim 14, characterised in that said layer of insulating material is at least one bentonite kerb or plug (21) .
16. System (1) according to claim 1, characterised in that said bell (3) is equipped on its lower side with catching and anchoring means to said wastes.
17. System (1) according to claim 16, characterised in that said catching and anchoring means are at least one sharpened or pointed edge (23) placed on a lower perimeter edge (25) of said bell (3) .
18. Disposing process for solid urban wastes in disposal tanks (9) by using a removable pyrolisation system (1) according to claim 1, characterised in that it comprises the steps of: a) delimiting at least one of said pyrolysation areas (7) in said disposal tank (9) through perimeter grooves (19) , said area (7) having sizes and shape compatible with said pyrolysation chamber (5) defined by said pyrolysing bell (3) capable of being transferred; b) descending said pyrolysing bell (3) capable of being transferred to its operation position above said area (7) to be treated; c) between said external surface of said bell (3) and said surrounding walls of said grooves (19) , arranging said layer of insulating material; d) activating said high-temperature heating means of said pyrolysation chamber (5) and starting said pyrolysis reaction of said wastes in said area (7); e) activating said mixers (18) to re-circulate said reaction gases inside said pyrolysation chamber (5) and to move said compacted wastes in said area (7) to be treated; f) simultaneously withdrawing said pyrolysis gases produced in said pyrolysation chamber (5) through said withdrawal duct (27); g) after having ended said pyrolysis reaction of said area (7), lifting and moving said pyrolysing bell (3) capable of being transferred; and h) repeating the previous steps for a new area (7) of said disposal tank (9) .
19. Process according to claim 18, characterised in that said step d) comprises the step of energising said electric resistances (11) .
20. Process according to claim 18, characterised in that it comprises the step of inserting said neutralising reagents inside said pyrolysation chamber (5) through said entry duct (29) . |
REMOVABLE PYROLISATION SYSTEM AND WASTE DISPOSING PROCESS USING SUCH SYSTEM.
The present invention refers to a removable pyrolisation system, in particular for the "in situ" heat treatment of solid urban wastes in disposal tanks with energy recover. The present invention further refers to a disposal process using a removable pyrolisation system.
As known, in some recent criteria for disposing solid urban wastes, it is provided for successively forming containing chambers inside a disposal tank, for forcedly introducing compacted and/or triturated wastes in such chambers and for airtightly sealing them till the tank itself was completely filled-in.
In general, the above containing chambers are formed of sheets of thermo-weldable polymeric material, typically polythene, and are flanked and overlapped one following the other.
Some systems for the heat treatment of solid urban wastes present in disposal tanks are known. In particular, patents n. IT-67286-A/90 and IT-A-TO93AOO055 of Servizi Ecologici s.p.a. disclose systems in which it is provided, after a suitable
maturing time, to dismantle the tank and recover the composted material to transfer it to treatment centers that are able to exhaust it with chemical and/or thermal transformations that allow separating an organic residue, aimed for example for agriculture, and the recovery of thermal energy, even if in very small amounts. The dismantled tank is then re-used, after having restored the containing chambers, for depositing a new load of wastes. This known waste disposing method, after composting in the above airtightly sealed tanks, is however labour intensive and economically unsatisfactory, because the yield in terms of recovered energy and recycled organic material is very low in comparison with the costs for installing and managing the treatment plant and the costs for dismantling the tanks and transporting the composted wastes.
In order to solve some of the above system problems, patent IT-A-TO93A000557, always of Servizi Ecologici s.p.a., discloses heat treatment plant, with energy recovery, for solid urban wastes in a disposal tank and its managing process. In particular, such plant provides for the use of a heating bell, capable of being transferred, therefore equipped with at least one high-temperature heat source that is able to produce a pyrolisis reaction, suspended to a removable trellis, that allows lowering the bell to an operating position thereof in contact with a surface layer of wastes contained in a disposal tank, in order to be able to pyrolise
in situ the wastes in individual tank areas by simply displacing the bell. Such plant however has some problems; in particular, it has no means or systems that guarantee the bell air-tightness. As known, however, pyrolisis is a thermochemical decomposition process of organic substances obtained by applying heat, that must occur with a complete absence of an oxidising agent, normally oxygen, to perform a thermally induced homolysis. Consequently, due to possible blows-by of external air inside the known bell when performing the pyrolysis reaction, flames could be generated, such as not only to corrupt the reaction efficiency, but even to place risks on the plant integrity and the safety of the personnel responsible for its operation. Moreover, the known bell, though for its operation it is provided that, due to its own weight, it descends inside the tank area by pyrolysing subsequent layers of wastes, it is not equipped with any means adapted to reliably guide such descent: it can therefore happen that, during the descent, the bell gets caught or descends slanted, due, for example, to a non-homogeneous arrangement of layers of wastes, again allowing entry of air inside the bell or preventing the correct operation of the disposal process.
Therefore, object of the present invention is solving the above prior art problems, by providing a removable pyrolisation system, in particular for the "in situ" heat
treatment of solid urban wastes in disposal tanks with an energy recovery that comprises at least one heating bell capable of being transferred and able to guarantee a better air-tightness.
Another object of the present invention is providing a removable pyrolisation system comprising at least one heating bell capable of being transferred that does not provide for its use for a pyrolysation under gravity descent of subsequent layers of wastes.
A further object of the present invention is providing a removable pyrolisation system comprising at least one heating bell capable of being transferred that can be used without the need of installing support structures, such as for example the prior art trellis, being therefore adapted to be transported and used in any disposal tank in a more economical and practical way.
Moreover, an object of the present invention is providing a disposal process by using a removable pyrolisation system.
The above and other objects and advantages of the invention, as will result from the following description, are obtained with a removable pyrolisation system, in particular for the "in situ" heat treatment of solid urban wastes in disposal tanks with energy recovery as described in claim 1.
Moreover, the above and other objects and advantages of the invention are obtained with a disposal process by using a
removable pyrolisation system as described in claim 18.
Preferred embodiments and non-trivial variations of the present invention are the subject matter of the dependent claims .
It will be immediately obvious that numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionality) can be made to what is described without departing from the scope of the invention as appears from the enclosed claims.
The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawings, in which:
- FIG. 1 shows a side sectional view of a preferred embodiment of the pyrolisation system according to the present invention; eand
- FIG. 2 shows a schematic top view of the pyrolisation system of FIG. 1.
In general, with reference to the Figures, the system 1 according to the present invention comprises at least one heating bell 3 capable of being transferred adapted to define at least one pyrolysation chamber 5 in order to subject to a pyrolysis reaction individual waste areas 7, such as for example those belonging to a disposal tank 9, as descried in the previously mentioned prior art patents. In particular, the heating bell 3 capable of being transferred is preferably
composed of at least one layer of refractory material, suitable to support operating temperatures higher than 800- 900 0 C, and is equipped with high-temperature heating means of the pyrolysation chamber 5: in a preferred embodiment of the system 1, the heating means comprise at least one electric resistance 11, or preferably a plurality of electric resistances 11 placed in series or in batteries inside at least one hollow space 13 defined by an internal wall 15a and an external wall 15b of the bell 3, such internal wall 15a being made of thermally conducting, preferably metallic, material and such external wall ' 15b being made of the refractory material. To obtain the most efficient high- temperature heating inside the pyrolysation chamber 5, the electric resistances 11 are preferably placed in contact with the internal wall 15a of the bell 3. To guarantee a suitable thermal insulation of the pyrolysation chamber, between the internal wall 15a and the external wall 15b of the bell 3 it is possible to provide for the introduction of at least one insulating layer 17 of a suitable material.
In a possible alternative, the heating means can be made as at least one plasma-type torch (not shown) substantially of a known type. It is however wholly evident that the heating means can be made in any other shape without anyway departing from the scope of the present invention.
In order to guarantee a better homogeneity in the area 7
to be treated of the pyrolysis reaction inside the pyrolysation chamber 5 and to move the compacted wastes in the area 7 to be treated, the bell 3 can be equipped with at least one automatic mixer 18, for example externally actuated by at least one electric motor 22, adapted to re-circulate the reaction gases inside the pyrolysation chamber 5 itself.
The bell 3 is then equipped with at least one withdrawal duct 27 of pyrolysis gases produced inside the pyrolysation chamber 5. The system 1 according to the present invention can therefore comprise at least one energy user (not shown) such as, for example, a power unit, a gas turbine or an alternative motor, supplied by the withdrawal duct 27 with the pyrolysis gas for producing electric energy.
As known, depending on type and nature of wastes to be subjected to pyrolysis, as result of the reaction, other potentially dangerous or damaging substances could also be produced, in addition to synthesis gases: in order to neutralise or better control such substances, the withdrawal duct 27 could be equipped with at least one filter with reagents, suitably chosen depending on the provided substance to be neutralised, through which the pyrolysis gas produced in the pyrolysation chamber 5 can be made flow. Alternatively or additionally, the bell 3 could also be equipped with at least one entry duct 29 of one or more neutralising reagents, also in this case suitably chosen depending on the provided
substance to be neutralised, inside the pyrolysation chamber 5.
Once having therefore delimited an area 7 to be subjected to pyrolysis through the system 1 according to the present invention, for example through grooves 19 with suitable sizes and depth obtained through an excavator in the disposal tank 9, it is enough to descend the bell 3 with its walls inside the grooves 19 in order to contain the waste area 7 inside the pyrolysation chamber 5. Obviously, to allow moving the bell 3, this latter one is equipped with fastening and moving means, made for example as at least one hook 20 placed on its top, to which it is possible to secure the lifting and moving means, such as for example a cable of a crane, an arm of an excavator, etc.
To guarantee a suitable seal against possible air seepages inside the pyrolysation chamber 5, between the external surface of the bell 3 and the walls surrounding the grooves 19, it is possible to place at least one layer of insulating material: in particular, preferably, such layer of insulating material is made as at least one bentonite kerb or plug 21.
Moreover, always to guarantee a suitable seal against possible air seepages inside the pyrolysation chamber 5, on its lower part the bell 3 can be equipped with catching and anchoring means to wastes being present on the groove 19 bottom. Preferably, as shown for example in FIG. 1, such
catching and anchoring means are made as at least one sharpened or pointed edge 23 placed on the lower perimeter edge 25 of the bell 3. It is wholly clear that such means can be made in any other shape without anyway departing from the scope of the present invention.
The present invention further refers to a disposal process for solid urban wastes in disposal tanks using a removable pyrolisation system like the previously dsribed one. In particular, the process according to the present invention comprises the steps of: a) delimiting at least one pyrolysation area 7 in the disposal tank 9 through perimeter grooves 19, such area 7 having sizes and shape that are compatible with the pyrolysation chamber 5 defined by the pyrolisation bell 3 capable of being trasferred; b) descending the pyrolysation bell 3 capable of being transferred to its operating position above the area 7 to be treated; c) between the external surface of the bell 3 and the surrounding walls of the grooves 19, arranging the layer of insulating material as, for example, at least one bentonite kerb or plug 21; d) activating the high-temperature heating means of the pyrolysation chamber 5, for example by energising the electric resistances 11; at that time, the pyrolysis reaction of wastes
in area 7 begins; e) activating the mixers 18 in order to re-circulate the reaction gases inside the pyrolysation chamber 5 and move the compacted wastes in the area 7 to be treated; f) simultaneously withdrawing the pyrolysis gases produced by the pyrolysation chamber 5 through the withdrawal duct 27; possibly inserting the neutralising agents inside the pyrolysation chamber 5 through the entry duct 29; g) after having ended the pyrolysis reaction of the area 7, lifting and moving the pyrolysing bell 3 capable of being transferred; and h) repeating the previous steps for a new area 7 of the disposal tank 9, for example an area 7 adjacent to the previously treated one.
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